Lac (Laccifer lacca) is an Indian animal origin drug. In Unani medicine Lac is known as Luk (Arabic word). Its medicinal properties are well advocated in unani literature. That’s why its use for various ailments is commonly prevailed among unani fraternity since centuries. This drug is very famous among unani practitioner for its anti-obesity effects. Various Unani medicine formulations (compound drugs) are having Lac as a chief constituent are in market. One of its most famous and acceptable formulation “Safoofe muhazzil” is being prescribed profoundly to counter obesity. Unani Scholars like Ibn Sina (Avicena), Razi, Ibn Rushd, Rabban Tabri, Hakeem Abdul Hakeem, Najmul Ghani, Jurjani and Kabeeruddin etc., wrote extensively about the medicinal use of Lac for various diseases in their respective books and treatises. Apart from Unani System of Medicine lac is also being used as drug in other complementary and alternative medicines (CAM) system especially in Indian system of medicine namely Ayurveda and Siddha.